Wavelength multiplexer/demultiplexer for optical circuits

A multimode wavelength selective beam monolithic coupler comprising:

• (a) an optically transparent substrate of a given index of refraction containing a layer of sufficient thickness and having a higher index of refraction forming a multimode optical waveguide, said substrate being further characterized by first and second end surfaces, said first end surface receiving and transmitting light;
• (b) a reflective diffraction grating affixed to said waveguide at said second end surface for diffracting said light which is propagated thereto from said first end surface, said second end surface being shaped so as to image said diffracted light onto said first end surface;
• (c) means adjacent said first end surface for transmitting light to said first end surface, said means for transmitting light comprising a plurality of spaced apart semiconductor lasers each having an output face abutting said first end surface of said waveguide and each emitting a different wavelength component of light, each of said semiconductor lasers being aligned at a preselected position along said first end surface so that light propagating from each of said sources to said grating is diffracted by said grating and is brought thereby to a common focus at said first end surface;
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• (d) means adjacent said first end surface at said said common focus for receiving light from any of said semiconductor lasers abutting said first end surface.

A wavelength multiplexer for optical circuits comprising:

• (a) an optically transparent substrate of a given index of refraction containing a layer having sufficient thickness and having a higher index of refraction forming a multimode optical waveguide, said substrate being further characterized by first and second major surfaces bounded by first and second end surfaces, said first end surface receiving and transmitting light;
• (b) a reflective diffraction grating having lines substantially perpendicular to said first and second major surfaces, said grating comprising a thin flexible material affixed contiguously to said second end surface for diffracting said light which is propagated thereto from said first end surface, said second end surface being convexly cylindrical with its axis of curvature aligned transversely to said first and second major surfaces and within the plane of said first end surface so as to image said diffracted light back onto said first surface;
• (c) a plurality of spaced-apart optical sources, each emitting a different wavelength component of light, wherein each source is adjacent said first end surface and aligned at a preselected position along said first end surface so that light propagating from each of said sources to said grating is diffracted by said grating and is brought thereby to a common focus at said first end surface;
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• (d) an optical fiber abutting said first end surface in position to receive said light from said common focus.

A wavelength demultiplexer for optical circuits comprising:

• (a) an optically transparent substrate of a given index of refraction contaning a layer having sufficient thickness and having a higher index of refraction forming a multimode optical waveguide, said substrate being further characterized by first and second major surface bounded by first and second end surfaces, said first end surface receiving and transmitting light;
• (b) a reflective diffracting grating having lines substantially perpendicular to said first and second major surfaces, said grating comprising a thin flexible material affixed continguously to second end surface for diffracting said light which is propagated thereto from said first surface, said second end surface being convexly cylindrical with its axis of curvature aligned transversely to said first and second major surfaces and within the plane of said first end surface so as to image said diffracted light back onto said first surface;
• (c) an optical fiber abutting said first end surface for transmitting light having a plurality of wavelength components into said wavelength so that said light propagates from said first end to said diffraction grating where it is diffracted by said grating into a set of beams having angles determined by said wavelength components and is brought thereby to a focus in the plane of said first end surface wherein each of said wavelength components forms a spatially separated image;
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• (d) a plurality of receiving means adjacent said first end surface, each receiving means aligned so that it receives a different one of said spatially separated images.